A system for making an emergency call to a service center in the event of a vehicle accident or the like has been put to practical use. For example, JP 4442619B corresponding to U.S. 2008/0204262A proposes a technique relating to this system. When an auxiliary battery is replaced after completion of an emergency call operation, the technique avoids wasting a battery capacity after the replacement.
As an emergency call system in a vehicle, there is a system that automatically makes an emergency call to a service center in conjunction with deployment of an airbag. This automatic emergency call is also referred to hereinafter as an airbag-linked emergency call. Presently commercially available vehicles include a vehicle compatible with the airbag-linked emergency call and a vehicle incompatible with the airbag-linked emergency call. In a typical airbag system compatible with the airbag-linked emergency call, a communication unit may be provided with a diagnosis function (malfunction diagnosis). For example, an airbag apparatus continuously outputs a signal (airbag signal) during non-deployment of the airbag. When this signal is interrupted, the communication unit determines the airbag is malfunctioned.
Now, let us assume a case where an in-vehicle communication apparatus compatible with the airbag-linked emergency call is mounted to a vehicle incompatible with the airbag-linked emergency call. In this case, since an airbag system is originally designed not to output the airbag signal, the airbag signal is not outputted as a matter of course, and thus, the airbag is wrongly diagnosed as being malfunctioned. Therefore, as to the in-vehicle communication apparatus of an emergency notification call, different in-vehicle communication apparatus products have been mounted to vehicles depending on whether a vehicle is compatible or incompatible with the airbag-linked emergency call. Therefore, an in-vehicle communication apparatus mountable to both of vehicles compatible and incompatible with the airbag-linked emergency call is desired.